Testing tool for insulation



Jan. 5 1926. 1,568,366

r M, DE MICHELI TESTING TOOL FOR INSULATION Filed June 21, 1924 PatentedJan. 5, 1926.

UNITED STATES MARIO nn MICHELE, or GENOA. ITALY.

TESTING TOOL FOR INSULATION.

Application filed June 21, 1924. Serial No. 721,528.

To all 10. mm it may concern:

Be it known t rat I, MAuio DE MIoHnLI, a citizen of Italy, residing atGenoa, Italy, have invented a. new and useful Testing Tool forInsulation, of which the following is a specification.

The object of the present invention is a testing tool for insulatingmaterials which essentially consists in an clectroscope in which thegold leaves are replaced by an oscillating lever. The electric charge isnot communicated to the tool from the outside by rubbing and contact,but by means of a device consisting of a rotatable part and a stationarypart forming elements of the tool.

The invention also includes an indicator connected with the oscillatinglever, which indicator cooperates with a graduation to point out thedegree of insulation of the material under test.

The invention has also for its purpose to provide atesting tool forinsulating means of very strong construction and sensitive ness which isas efiicient as the known electroscopes provided with gold leaves. Thetool operates safely and all its parts are enclosed in a casing.

The invention is illustrated in the accompanying drawing.

Fig. 1 shows a front view of the tool with the cover omitted;

Fig. 2 is a vertical sectional view of the same, with the coverq'nposition.

Fig. 3 is a face view of the cover.

1 is a metal casing arranged on the pedesta] 2. The casing 1 carries atthe back side a flange 3 and at the front side a threaded edge a for themetal ring which carries the glass cover 6. In the vertical middle plantin the casing l. arranged a rectangular metal leaf 7. This leaf iscarried by a pin 8 threaded in the metal head 9. This latter is fastenedon the casing 1 by means of the ebonite plug 10. In the central partofthe leaf 7 is an opening 11 limited axially of the casing by two ribs.In these ribs is supported a shaft 12, which at its front end carries apointer 18. Upon the part of the shaft 12 within the opening 11 oneither side of the metal leaf 7 are applied two thin aluminum leaves 14and 14. The same are situated in planes parallel to each other and invertical position they can adhere against the faces of the leaf 7. Asthe Weight of the leaf 14. slightly less than the weight of the-upperleaf 14, these leaves maintain this position of contact if the tool isnot charged.

The casing 1 is closed at the back by a metal disc 15, which by its edge16 and four metal arms 17, engage the flange 3 so that the disc can berotated on the casing 1. The ClISC 15 carries centrally a glass pane 18and on its inner side an ebonite ring 19 which can be rotated from theoutside by grasplng and turning the toothed edge 16 of the disc 15.Diametrically opposite each other in horizontal alignment are arrangedtwo metal leaves 20 carried by a semi-circular metal ring 21, which isfastened on the casing 1. by a screw. Each of the metal leaves 20carries on its inner side, a strip of wool against which the ebonitering 19 rubs during its rotation. The semi-circular metal ring 21 has anotch 22 opposite the lower end of the metal leaf 7 in order to spacethe metal parts 7 and 21. The pin 8 carries a contact piece 23 whichslides on the ebonite ring 19. The inclination of the pointer is degreesfrom the vertical when the two leaves l t-14 (at loaded tool) are in ahorizontal position, and the pointer assumes a position 90 degrees awayafter the discharge, that is when the leaves 141&" are in the verticalposition. Between these two extreme positions of the pointer, the coverof the casing carries graduations which facilitate the establishment ofthe in termediate values of the capacity of insulation.

In order to test insulating material with the nresenttool the disc 15 isoscillated for about a half a revolution in one direction or the other.Due to this rotatici'l, static electricity is generated as the annularebonite piece 19 rubs against the strips of wool fastened on the metalleaves 20. The static electricity produced is sufficient to displace theoscillating lever, constituted by the arms 14, 14. arranged on the shaft12. The oscillating lever, when the tool is unloaded, rests with its arm14: uppermost and with this arm bearing against the left hand of themember 7 while the arm 14 bears against the right hand side of the lowerportion of the member 7. The electricity thus generated is conducted bymeans of the contact piece 23 to the pin 8 and from thispin 8 to themember 7, against which the oscillating lever 14, 14 is hearing. Onaccount of the fact that bodies charged with electricity of the samesign have a tendency to repel one another, the oscillating lever isrepelled by the member 7 and it thus rotates into the position shown inFigure 1. At this time if the insulating material to be tested is placedagainst the metal head 9, the oscillating lever l t, 1% will maintainits horizontal position, pro iding the insulating material is perfect.If the material undergoing test does not have good insulatingproperties, the lever returns to its vertical position where it againbears against the member 7. It is to be noted that the arm 1 is slightlyheavier than the arm 14:, so that the lever always has a tendency toreturn to its original vertical position. where it remains as long asthe device is not charged with static electricity. it is to beunderstood, that in order to establish the different degrees ofinsulation of the bodies undergoing test, it is necessa y that the head9 be touched for an instant only. According to the position which theindicator assumes relatively to the scale 50. the degree of insulationcan be determined.

The tool is not only adapted for the examination of insulating materialbut may be used to distinguish cotton or mixed fabrics from those ofpure wool and pure silk from artificial silk, as well as to establish ifpure silk or wool have been excessively dressed.

The tool can be built in small dimensions so that it can be put in thepocket. and this without affecting its solidity, sensibility andreliableness of working.

l. in electrostatic tool for testing insulatuaterial comprising acasing. a rotatable ring in the casing, means for rotating said ringfrom the exterior of said casing, stationary brushes of textile materialbearing against said ring, a metallic member in the casing, means fortransmitting static elecricity from the ring to said member, an elementconnected to said means and adapted to be contacted with the insulatingmaterial to be tested, an oscillating lever associated with said memberand including a plurality of contact surfaces adapted to normally bearagainst said member, a pointer rotatable with the lever, and a scalecooperating with said pointer.

2. An electrostatic tool for testing insulating material comprising acasing, a rotatable ring in the casing, means for rotating said ringfrom the exterior of the casing, stationary brushes of textile materialbearing against said ring, a metallic leaf in the casing, means fortransmitting static electricity from the ring to said leaf, an elementconnected to said means and adapted to be contacted with the insulatingmaterial to he tested, an oscillating lever associated with said leafand including a plurality of arms adapted to normally bear gainst saidleaf, a pointer rotatable with the lever, and a scale cooperating withsaid pointer.

An electrostatic tool for testing insulating material including acasing, a ring member arranged in the casing, a brush member in thecasing contacting with the ring member, said members being of suchmaterial that when one of the members is rubbed on the other, staticelectricity will be generated, means for moving one of the members fromthe exterior of. the casing, a leaf of conducting material arranged inthe casing, means for conducting static electricity generated by saidmembers to the leaf, an element connected to said means and adapted tobe contacted with the insulating material to be ested, an oscillatinglever associated with the leaf and adapted to normally bear against thelatter and to be forced away from the leaf by static electricitygenerated by said members, a pointer movable with said lever, and ascale cooperating with said pointer.

In testimony whereof I have signed my name to this specification.

MARIO DE MIC/HELL

